Start using legacy date-stamp to remain consistent changelog

Resolve: BZ #1760416

Sed command get version number from spec file and increment last
number by one. Work like old awk command was intended to work.

Source: https://stackoverflow.com/questions/14348432/how-to-find-replace-and-increment-a-matched-number-with-sed-awk/14348899

  This will allow services to install drop-in files into these folders
  for the 'readonly-root' service, but that service won't have to be
  installed by default as a result...

  Resolves: RHBZ#1585321

  This concept is quite outdated, and not sane to use at all.

  Use 'git log' instead...